Magnesium oxide, more commonly called magnesia, is a mineral that when used as part of a cement mixture and cast into thin cement panels under proper curing procedures and practices can be used in residential and commercial building construction. Some versions are suitable for general building uses and for applications that require fire resistance, mold and mildew control, as well as sound-control applications. Magnesia board has strength and resistance due to very strong bonds between magnesium and oxygen atoms that form magnesium oxide crystals (with the chemical formula MgO).
Magnesia boards are used in place of traditional gypsum drywall as wall and ceiling covering material and sheathing. It is also used in other construction applications such as fascias, soffit, shaft-liner and area separation, wall sheathing, and as tile backing (backer board) or as substrates for coatings and insulated systems such as finish systems, exterior insulation finishing systems, and some types of stucco.
Magnesia cement board for building construction is available is various sizes and thickness. It is not a paper-faced material. It generally comes in light gray, white or beige. Grades include smooth face, rough texture, utility and versatile, and there are different densities and strengths for different applications and uses.
Various magnesia cement boards are used in Asia as a primary construction material. Some versions have been designated as the official construction-specified material of the 2008 Summer Olympics, and some versions are used extensively on the inside and outside of all the walls, fireproofing beams, and as the sub-floor sheathing in one of the world's tallest buildings, Taipei 101, in Taipei, Taiwan.
Magnesia cement is manufactured around the world, primarily near areas where magnesia-based ore (periclase) is mined. Major deposits are found in China, Europe, and Canada.[1] Magnesia ore deposits in the US are negligible. Estimates put the use of magnesia board products at around 740,000 square metres (8 million square feet)[clarification needed] in Asia. It is gaining popularity in the US, particularly near coastal regions.